Yesterday, my t.v. went into standby after 5 minutes of non-use, and will not come out of it! The set is roughly two years old and is hardly ever used. When out of use, it is always covered over with the original bag and the power source disconected. It is used only for watching the odd video or dvd.
The battery in the handset is ok!
those cheap sets are usually pretty dire when it comes to longevity. you get what you pay for! It's probably a Vestel or profili chassis.
From my experience, I'd say the line stage has developed a short and the power supply is protecting itself. take it to a tech.